RESUMO
The Wide Area Demonstration (WAD) was a field exercise conducted under the U.S. EPA's Analysis of Coastal Operational Resiliency program, in conjunction with the U.S. Department of Homeland Security and the U.S. Coast Guard. The purpose of the WAD was to operationalize at field scale aspects of remediation activities that would occur following an outdoor release of Bacillus anthracis spores, including sampling and analysis, decontamination, data management, and waste management. The WAD was conducted in May 2022 at Fort Walker (formerly known as Fort A.P. Hill) and utilized Bacillus atrophaeus as a benign simulant for B. anthracis. B. atrophaeus spores were inoculated onto the study area at the beginning of the study, and air samples were collected daily during each of the different phases of the WAD using Dry Filter Units (DFUs). Ten DFU air samplers were placed at the perimeter of the study area to collect bioaerosols onto two parallel 47-mm diameter polyester felt filters, which were then subsequently analyzed in a microbiological laboratory for the quantification of B. atrophaeus. The study demonstrated the use of DFUs as a rugged and robust bioaerosol collection device. The results indicated that the highest B. atrophaeus spore air concentrations (up to ~ 5 colony forming units/m3) occurred at the beginning of the demonstration (e.g. during inoculation and characterization sampling phases) and generally downwind from the test site, suggesting transport of the spores was occurring from the study area. Very few B. atrophaeus spores were detected in the air after several weeks and following decontamination of exterior surfaces, thus providing an indication of the site decontamination procedures' effectiveness. No B. atrophaeus spores were detected in any of the blank or background samples.Implications: Following an incident involving a release of Bacillus anthracis spores or other biological threat agent into the outdoor environment, understanding the factors that may affect the bioagent's fate and transport can help predict viable contaminant spread via the ambient air. This paper provides scientific data for the first time on ambient air concentrations of bacterial spores over time and location during different phases of a field test in which Bacillus atrophaeus (surrogate for B. anthracis) spores were released outdoors as part of a full-scale study on sampling and decontamination in an urban environment. This study advances the knowledge related to the fate and transport of bacterial spores (such as those causing anthrax disease) as an aerosol in the outdoor environment over the course of three weeks in a mock urban environment and has exposure and health risk implications. The highest spore air concentrations occurred at the beginning of the study (e.g. during inoculation of surfaces and characterization sampling), and in the downwind direction, but diminished over time; few B. atrophaeus spores were detected in the air after several weeks and following decontamination. Therefore, in an actual incident, potential reaerosolization of the microorganism and subsequent transport in the air during surface sampling and remediation efforts should be considered for determining exclusion zone locations and estimating potential risk to neighboring communities. The data also provide evidence suggesting that the large-scale decontamination of outdoor surfaces may reduce air concentrations of the bioagent, which is important since exposure of B. anthracis via inhalation is a primary concern.
RESUMO
Large-scale biological contamination incidents pose unique yet significant challenges to remediation operations. Previous incidents have demonstrated the utility of readily available commercial and municipal equipment for conducting remediation tasks. Preidentification and evaluation of such equipment could reduce lag time for response initiation and enhance overall response effectiveness and efficiency. The current study aimed to identify commercial and municipal equipment that could be beneficial in wide-area biological remediation operations. Equipment were identified by market research, their utility was assessed by a group of subject matter experts, and a subset of those equipment was observed under operational conditions in a realistic urban environment. Observations and feedback from demonstration participants are presented within the article. This information is intended to support rapid decision-making following large-scale biological incidents, broaden the universe of potentially useful equipment to support the response, enhance response operations, and reduce the impact on the public.
RESUMO
This paper describes the modeling approach and example results for a newly introduced computational simulation tool to evaluate waste destruction in thermal incineration systems. The Configured Fireside Simulator (CFS) is a software simulator, originally developed for the Department of Defense to evaluate operations of the chemical demilitarization incinerators processing the chemical warfare agent stockpile of the US. The software was later adapted for use by the U.S. Environmental Protection Agency (EPA) to provide for the ability to run "what if" scenarios of waste streams contaminated with chemical/biological (CB) threat agents in four specific incinerators, including the EPA's pilot-scale Rotary Kiln Incinerator Simulator (RKIS) facility, as well as three commercial incinerators based on design criteria for actual operating facilities. These commercial incinerators include a Medical/Pathological Waste Incinerator, a Hazardous Waste Burning Rotary Kiln, and a Waste-to-Energy Stoker-type combustor. The CFS uses three-dimensional computational fluid dynamics coupled with detailed chemical kinetic data for destruction of chemical warfare agents, coupled with kinetic data for biological agent destruction derived from bench- and pilot-scale experiments to predict the way agent-containing materials will behave under full-scale combustion conditions in several different incinerator types. The objective of this paper is to describe the CFS software, how it works, and potential applications of this software to real-world situations. This software could be a valuable tool for researchers, regulators, and industry to evaluate potential operating conditions to help guide testing activities and develop operational scenarios for difficult-to-manage waste streams. Although this software has been under development for several years, this paper represents the software's first introduction to the scientific community in the peer-reviewed literature.Implications: Adapting the Configured Fireside Simulator that was originally developed for the Department of Defense to evaluate operations of the chemical demilitarization incinerators processing the chemical warfare agent stockpile of the US to provide for the ability to run "what if" scenarios on civilian waste streams contaminated with CB agents is a useful tool for national preparedness. Such a model could be used in planning and response efforts to provide a better understanding of incineration capacity, development of feed strategies, and assessment of throughput limitations for CB incidents as well as other difficult-to-test waste streams and contaminants.
